This invention relates to attachments for a shotgun, and in particular to an attachment for use with the muzzle end of a shotgun barrel.
It is known to use shotguns as breaching tools to disable the hinges or locks of a door to gain entry through an otherwise locked door. Typically such breaching tools have a stand-off arrangement at the muzzle end of the shotgun barrel, either permanently affixed thereto, or threaded onto the fine interior threads in the shotgun barrel.
The stand-off device is generally a cylindrical tube which extends beyond the muzzle end of the barrel and contains passages to allow gasses from the fired shotgun shell to exit laterally while permitting the shot from the shell to continue along an axial extension of the barrel to engage the door surrounding the lock or hinge.
In order to use such a stand-off device, it is necessary to thread the device onto the shotgun barrel, and due to the very fine threads provided on the interior of the barrel, this requires a significant amount of time to complete the many rotations of the standoff until it sealingly seats in the barrel. The length of time required to engage and disengage the stand-off has resulted in dedicating a shotgun to only the task of being used as a breaching tool and to prevent the same shotgun from being used in a given law enforcement or military operation for an other purpose.
If the stand-off is made a permanent part of the shotgun barrel, then certainly that shotgun is limited to a single purpose. When a shotgun is limited to a single use, then either additional personnel are required to man the various weapons and tools required for a particular operation, or various personnel are required to carry more than one weapon or tool and are required to change carrying positions and other considerations which can lead to dangerous situations.
Typically the sole means of attachment of these stand-offs is the meshing of the fine thread of the interior of the barrel and the exterior of the stand-off tube. This provides only a single point of attachment and this attachment is secured only by snugging the seating of stand-off tube against the shoulder on the inside of the barrel
This single point of attachment, in a cantilevered fashion, is subject to loosening due to vibrations occurring during the firing tube of the shotgun, from recoil, internal pressure and also the passage of the shot charge, wad and propelling gasses, if the stand-off tube is not continuously checked for tightness, a hazardous condition resulting from a loose tube could result. The tube can loosen from its proper position in the bore, by way of the backing-out of its threads or else by lateral vibration and movement. The resulting hazards may include the failure of the stand-off tube-to-bore gas seal, the deformation of the dimensions of stand-off tube, the threads and the bore of the barrel, which can occur with catastrophic result. The instability of such cantilevered seating of the tube also negatively affects the pellet patterning efficiency and consistency of the shotgun stand-off tube even when properly seated.
It would therefore be an improvement in the art if there were provided a means for securing the attachment of the breaching tool that would minimize or prevent the unwanted loosening and lateral instability of the breaching tool.
It would also be an improvement in the art if there were provided a means for attaching breaching tubes, in a stable and secure manner to a shotgun barrel, and to be able to do so in a less time consuming manner than utilizing the fine threaded attachment arrangement provided on the interior of the shotgun barrel.
It is an object of the present invention to provide a means for securing the attachment of the breaching tool for a shotgun barrel, that would prevent the unwanted loosening of the breaching tool.
It is also an object of the present invention to provide a means for attaching breaching tools, in a secure manner, to a shotgun barrel, in a less time consuming manner than utilizing the fine threaded attachment arrangement provided on the interior of the shotgun barrel.
These objects are inventively achieved in one embodiment where a locking arrangement for a shotgun breaching tool is provided, wherein the shotgun breaching tool comprises a cylindrical carrier tube having a first external threaded portion at one end for threadingly engaging an internal thread in a shotgun barrel which is spaced inwardly of a muzzle end of the shotgun barrel and which firmly seats that first portion of the tube to the bore and seals it. Also, a lateral notch, slot or other device or surface feature may be located at the opposite or forward end of the exposed carrier tube beyond the muzzle end of the shotgun barrel, so as to permit the carrier tube""s internal seal and threads to be initially firmly seated and tightened. The stabilizing locking arrangement comprises a second external threaded portion on the carrier cylindrical tube, which second portion will remain exposed beyond the muzzle end of the shotgun barrel when the carrier is fully threaded into engagement with the bore of the shotgun barrel. An internally threaded stand-off tube is provided which is sized to be threadingly carried on an outside of the carrier tube and to engage the second external threaded portion of the carrier tube such that the stand-off tube can be threaded onto the carrier tube until it tightly and abuttingly securely engages the muzzle end of the shotgun barrel, providing an additional seating point adding to the longitudinal, lateral and axial security, seat and stability of the carrier tube.
The objects are inventively achieved in a further embodiment where a carrier tube and stand-off tube assembly for use with a shotgun barrel is provided comprising a cylindrical carrier tube with a first externally threaded portion at one end for threadingly engaging an internal thread in the shotgun barrel which is spaced inwardly of a muzzle end of the shotgun barrel, and a second externally threaded portion which will remain exposed beyond said muzzle end of said shotgun barrel when the carrier tube is fully threaded into engagement with the shotgun barrel. An internally threaded stand-off tube is also provided which is sized to be threadingly carried on an outside of the tube and to engage the second externally threaded portion of the tube such that the stand-off tube can be threaded onto the tube.
Other embodiments provide additional features of the invention as described in greater detail below.